Energy imbalance is a major health problem in the US that is related to poor quality of life and increases the risk of several diseases, including coronary heart disease, cancer and diabetes. Room respiration calorimeters are the standard for long-term and high resolution measurements of energy expenditure and substrate oxidation. Yet, room calorimeters aren't available to many physiologists and physicians who would like to use them because they have to build their own. Devicix plans to apply rigorous systems engineering methods to design a calorimeter that is validated as reliable and efficient. Our goals are to maximize performance and minimize the financial and operational burdens to purchase, install and operate a room calorimeter. PUBLIC HEALTH RELEVANCE: Whole-body respiration calorimeters are an important tool for research into the causes and treatments of overweight and poor nutrition. Ever since these calorimeters were first used more than 100 years ago investigators have had to build their own. This Lab- to-Market project will optimize the performance and reduce the cost of a whole-body calorimeter design and make them available as a commercial product.